Amblyopia: what does the future hold?
- Correspondence to Dr Ken K Nischal, Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK; kkn{at}btinternet.com
In this issue, Petermeier et al(see page 1296) report their results of implantation of a diffractive multifocal intraocular lens (IOL) for three adults with mild to moderate unilateral amblyopia, who had bilateral cataracts.1 There has been understandable caution in the use of multifocal IOLs in amblyopic eyes not only because of the reduced visual acuity which may interfere with the binocular experience but also because of deficits such as the crowding phenomenon and reduced contrast sensitivity.
Diffractive multifocal IOLs produce more than one image on the retina, but depending on the focal length desired (near or far), one image will be clearer and sharper than the other. There is a learnt neuroprocessing within the visual system, even in non-amblyopic eyes, that allows patient to become comfortable with this visual experience; could the crowding phenomenon affect such processing? These IOLs are also known to reduce contrast sensitivity,2 which may be detrimental for both near and distance vision in an amblyopic eye.
One patient had bilateral clear lens extraction for hyperopic presbyopia, and two others had bilateral cataract. In the two cases with cataracts, the best-corrected visual acuity (BCVA) preoperatively in the amblyopic eyes was 6/60, improving to 6/7.5 postoperatively, while the patient with clear lens extraction improved his uncorrected visual acuity in his amblyopic eye but not his best corrected acuity. While the use …
